INTESTINAL GLYCOSIDASE ACTIVITIES IN THE HUMAN EMBRYO, FETUS, AND NEWBORN

Abstract

1. In 32 human embryos, fetuses, newborns, and infants α-glycosidase activities (maltase, sucrase, isomaltase, palatinase, trehalase, dextranase, and amylase) and β-glycosidase activities (lactase and cellobiase) of the small intestine were determined. 2. The enzyme activities are distributed uniformly throughout the small intestine except in duodenum and terminal ileum. Lower values were found in these areas except for trehalase which remained high in the terminal ileum. 3. All glycosidases are present by the third month of intrauterine life. Most of the α-glycosidase activities reach maximal values by the 6th to 8th fetal month. Levels of activity are independent of the period lapsed since birth and independent of previous food intake. Only amylase and maltase 1 activities are low at birth in the full-term newborn. 4.β-glycosidase activities reach maximum values only at the end of normal gestation. After premature birth development of β-glycosidase activity occurs rapidly. 5. The observed development of the intestinal disaccharidases in the human is apparently different from that known in animals (calves, rabbits, pigs, and rats), where the α-disaccharidases develop only after birth and where lactase activity develops earlier in fetal life and drops after birth.